Roof insulation
Thermal insulation works on the roof, the top priority for improving energy performance.
Full definition
Roof insulation is considered the most cost-effective energy renovation measure, as 25 to 30% of a building's heat loss occurs through the roof. In Belgium, minimum standards for roof insulation are set by the regions: a minimum thermal resistance coefficient R of 4 to 6 m2K/W is recommended. Common materials are glass wool, rock wool, sprayed polyurethane (PUR), and extruded polystyrene (XPS). Average cost is EUR 30 to 80/m2 including installation. Regional grants are significant: in Wallonia, EUR 6 to 20/m2 depending on income; in Flanders, via Mijn VerbouwPremie; in Brussels, via RENOLUTION. In Flanders, roof insulation is mandatory when purchasing a non-compliant property (5-year deadline).